Decoding method for receiving ofdm signals, and decoding apparatus and receiving apparatus using the same

Abstract

A phase derivation unit derives a phase difference between two symbols for each subcarrier, based on phase components of symbols. A weighting factor derivation unit derives a weighting factor for each subcarrier, based on amplitude components of the symbols. A multiplier weights the phase difference with the weighting factor for each subcarrier. A likelihood accumulation unit accumulates the weighted phase differences for a plurality of subcarriers. A decision units determines a result of accumulation. A substitution unit identifies a portion where known data are to be assigned, among the determined data frames, and substitutes the data in the identified portion with known data. A syndrome computation unit performs a syndrome computation on the data frames. An error detector detects an error in the data frames, based on a result of the syndrome computation.

1 . A decoding apparatus, comprising:
 an input unit which inputs a block-coded data frame;   a substitution unit which specifies an area, where known data are to be assigned, among the data frame inputted in said input unit and which substitutes data in the specified area with the known data;   a computing unit which performs syndrome computation on the data frame substituted by said substitution unit; and   a detector which detects an error in the data frame, based on a result of syndrome computation performed by said computing unit.   
   
   
       2 . A decoding apparatus according to  claim 1 , wherein a frame synchronization codestream is contained in the data frame inputted in said input unit, and
 wherein said substitution unit acquires the frame synchronization codestream in advance, specifies an area, where the frame synchronization codestream is to be assigned, among the data frame inputted in said input unit, and substitutes data in the specified area with the frame synchronization codestream.   
   
   
       3 . A decoding apparatus according to  claim 1 , wherein a frame number is contained in the data frame inputted in said input unit, and
 wherein said substitution unit acquires the frame number in advance, specifies an area, where the frame synchronization codestream is to be assigned, among the data frames inputted in said input unit, and substitutes data in the specified area with the frame number.   
   
   
       4 . A receiving apparatus, comprising:
 a receiver which receives a multicarrier signal where control signals are assigned to at least two subcarriers and data signals are assigned to the remaining subcarriers;   a separator which separates the multicarrier signal received by said receiver into the control signals and the data signals;   a first demodulator which demodulates the control signals separated by said separator; and   a second demodulator which demodulates the data signals separated by said separator,   said first demodulator including:
 a substitution unit which specifies an area, where known data are to be assigned, among a block-coded data frame and which substitutes data in the specified area with the known data, the data frame being data frame of the control signals separated by said separator; 
 a computing unit which performs syndrome computation on the data frame substituted by the substitution unit; and 
 a detector which detects an error in the data frame, based on a result of syndrome computation performed by the computing unit. 
   
   
   
       5 . A decoding method, comprising:
 inputting a block-coded data frame;   specifying an area, where known data are to be assigned, among the inputted data frame and substituting data in the specified area with the known data;   performing syndrome computation on the substituted data frame; and   detecting an error in the data frame, based on a result of syndrome computation.   
   
   
       6 . A computer readable medium encoded with a computer program product for performing the steps of:
 inputting a block-coded data frame;   specifying an area, where known data are to be assigned, among the inputted data frame and substituting data in the specified area with the known data;   performing syndrome computation on the substituted data frame; and   detecting an error in the data frame, based on a result of syndrome computation.